PROJECT SUMMARY The growing availability of wearable monitors that measure personal exposure to air pollution represents a paradigm shift in exposure assessment, epidemiologic research, and citizen-science. In contrast to fixed monitoring sites or models to estimate air pollution exposure, personal monitors provide individual-level and actionable data that requires novel human subjects considerations. Previous biomonitoring studies that measure environmental exposures in biological samples demonstrate that providing participants their individual results in a meaningful way is beneficial to both participants and researchers. However, studies using personal air monitors have not engaged participants and other stakeholders to develop understandable and actionable individual reports nor examined whether individual reports influence knowledge, behaviors, or personal air pollution exposure. Therefore, the primary objective of this proposal is to engage study participants and their caregivers to develop effective report-back strategies for personal air pollution monitoring results. In addition, we will examine the impact of providing individual results from personal air monitors on participants? environmental health knowledge. We will build upon our ongoing study of adolescents? personal exposure to ultrafine particles where our data demonstrate that real-time air pollution monitoring, in conjunction with GPS coordinates, provides personal exposure information and compelling visualizations of when and where exposures occur through space and time. In Aim 1, we will engage study participants and their caregivers to inform the development of meaningful report-back materials that are easy to understand and provided in a format preferred by the intended audience. In Aim 2, we will develop and evaluate the report-back materials, including a novel visualization tool that allows participants to interact with their data. We will also conduct an exploratory study (Aim 2.1) to determine whether providing individual results of personal air monitoring improves environmental health literacy and examine the potential for this information to influence changes in behavior. Given the increasing use of personal air monitors in research studies, citizen-science activities, and among general consumers, data from personal air monitors accompanied by GPS coordinates offers the potential to provide actionable information to inform behavioral modifications and guide exposure reduction strategies. This information may be especially useful to susceptible individuals who may experience more healthy days with increased knowledge regarding locations and times of highest air pollution exposure.